Breakdown voltage is an important parameter for many semiconductor devices because it often determines limits of a semiconductor device's operation voltage range. In order to increase breakdown voltage of a semiconductor device, several methods are commonly in use, for example: reducing doping concentration of a region between two electrical terminals (e.g., between source and drain, anode and cathode, or gate and drain . . . etc.) or increasing the distance of between the two terminals.
When designing a semiconductor device, certain parameters are often fixed in order to achieve a certain performance goal, while some other parameters may be adjusted to further enhance the overall device performance. For example, in order to achieve a certain threshold voltage for a metal oxide semiconductor field effect transistor (MOSFET), doping concentration of a channel region, which is between source and drain regions (“the two terminals”), is fixed. Breakdown voltage between the two terminals can be increased by increasing the distance between the two terminals (for example by adding a drain extension region between the drain region and the channel region) without substantially affecting the threshold voltage.
However, an increase of the distance between the two terminals increases device footprint, which may reduce the number of devices which can be manufactured per unit area on a wafer and may thus increase manufacture costs.
Thus, there exists a need in the art for developing a semiconductor device, capable of scaling the distance between two terminals to improve device performance (for example, a greater breakdown voltage) without substantially increasing the device footprint.